Crank size markings

[Old Sparky]

I have a 1970 440 6 pack engine....and am wondering if anyone has found out for sure what the letters on the back of the bearings mean. The ID pad is stamped with a "B" which means the crank is .010 under size.
The bearings in this engine have a "D" stamped on the back....which is the only markings found. I have an original Chrysler service manual I bought with my Super Bee and it gives factory under sizes of .001 .002 .003 .010 and .012 Is it correct in thinking that the letters A B C D E on the backs of bearing correlate to these sizes? This would be correct for my engine as being "D" = .010 undersize. Looked all over the web and have found no definite proof that this is the case. Anyone else located this info.

Thanks
Sparky

 

[Fran Blacker]

Look on the crank counter weighs if it's factory won't tell undersize. My 66 had .001 us on the back of number 5 main and 5/6 7/8 rods.

 

[Old Sparky]

Look on the crank counter weighs if it's factory won't tell undersize. My 66 had .001 us on the back of number 5 main and 5/6 7/8 rods.View attachment 1167370

 

[Old Sparky]

I am familiar with those marks but have none of them.
The only mark on the crank is a "6" for the sixpack on the first weight and a "U"
on the last weight which I can't rem what it means right now.
As I remember the marks you are referring to are if the crank is not the same all the way thru.....mine is noted to be .010 under all the way....am just looking for confirmation on my theory that the bearing letters correspond to the factory crank sizes

 

[Fran Blacker]

I thought that it might not have numbers like mine. What your saying about ABCD is logical. I rather it said on bearing U/S .010 for anybody who doesn't know about factory markings.

 

[Old Sparky]

I thought that it might not have numbers like mine. What your saying about ABCD is logical. I rather it said on bearing U/S .010 for anybody who doesn't know about factory markings.

Yes I wish the same...at least it would be a sure thing

 

[Old Sparky]

I thought that it might not have numbers like mine. What your saying about ABCD is logical. I rather it said on bearing U/S .010 for anybody who doesn't know about factory markings.

Hello
What I was saying about the bearing letters is starting to look good except for one thing....I forgot about STD bearings.
Therefore: A=STD B=.001 C=.002 D=.003 E=.010 F=.012 undersize bearings.....seems to be logical.....do not know why the marking like you have are not on mine....my #1+2 mains have a "B", #3 has a "D", #4+5 have a "e".
Seems to sound logical like you say....hope someone else has noticed this.....my thinking mine was undersize .010 all the way was wrong, I misinterpreted what was on the ID pad.

 

[Fran Blacker]

Do you a digital or dial caliber or better yet a 2 to 3 inch micrometer? The caliper is +/-.001 that will get you close but an accurate micrometer will give answers. If you have no access to a micrometer you need to go to a machine shop. They can measure if a journal is round any taper and diameter. Guessing numbers on bearings isn't the way to do it.

 

[Old Sparky]

Do you a digital or dial caliber or better yet a 2 to 3 inch micrometer? The caliper is +/-.001 that will get you close but an accurate micrometer will give answers. If you have no access to a micrometer you need to go to a machine shop. They can measure if a journal is round any taper and diameter. Guessing numbers on bearings isn't the way to do it.

Hi
I have a mic coming in the mail soon....not really guessing on the crank , just trying to figure the letters for future use, a bit of curiosity.